This invention relates to a hot-cold water mixing valve, in which, the outlet water temperature is adjusted by rotating the valve handle connected to the valve stem.
Each time a person goes to take a shower or bath, he must go through a routine of repeatedly adjusting handle position and feeling water temperature until a desired temperature being obtained. This trial-and-error routine is time consuming and wastes water. Also during a shower, the user may need to turn off the valve for soaping, and turn on the valve again after soaping. Going through the trial-and-error routine during a shower is particularly inconvenient.
One prior approach to the above problems is to provide a mixing valve with two handles. One handle is to turn the valve on and off, so as to control water flow rate. Another handle is to control water temperature only. The drawbacks of this approach are: (1). Such a valve consists of more complicated components and becomes more expensive. (2). In order to quickly flush out residual cold water in the hot water pipe, user may prefer to set the valve handle at maximum hot temperature position prior to taking a shower. As a result, the user still needs to go through the trial-and-error routine to adjust the valve handle position to obtain the desired temperature position.
Another prior approach to the above problems is to provide position indicating marks. It is a common knowledge that at least two individual marks are required to determine the position of the valve handle (i.e., the degree of rotation of handle), one on the handle, and one on a stationary element of the valve. The relative movement between the two marks indicates the degree of rotation of handle. Based on this common knowledge, a group of marks can be provided on a stationary element of the valve, and another group of marks can be provided on the handle. When user rotates the handle to the desired temperature position, he needs to memorize the particular mark on the stationary element that is in line with the particular mark on the handle. The next time when the user needs to turn the handle to the desired temperature position, he can rely on his memory to recall and align the two particular marks. This type of prior approach can be found in U.S. Pat. Nos. 6,052,929 and 6,343,619. The obvious drawback of this approach is that user must memorize the marks at all time. Another obvious drawback is that multiple marks are difficult to read.
Another prior approach to the above problems is to provide position indicating marks that can pre-set the handle to the desired temperature position. This approach provides two position indicating marks, one fixed mark and one moveable mark. The first step to pre-set handle to the desired temperature position is to rotate handle to the desired temperature position by trial-and-error. The second step is to move the moveable mark to meet the fixed mark. After the handle is pre-set, user can rotate handle directly to the desired temperature position by aligning the fixed and moveable marks. This type of prior approach can be found in U.S. Pat. Nos. 5,170,816, and 6,283,447.
In U.S. Pat. No. 5,170,816, Schneider proposes a fixed mark on a stationary element of the valve, and multiple moveable marks on multiple small moving parts that side in a slot on the valve handle. There are several drawbacks in Schneider's approach. First, the moveable marks on small moving parts (i.e., sliding parts) are difficult to maneuver. Second, the slot and multiple moveable marks are difficult to be cleaned. Mildew can build up in the slot and in the hidden areas behind the moveable marks. Third, it is impossible to clean the hidden areas behind the moveable marks without moving the moveable marks. As a result, the moveable marks need to be pre-set each time after cleaning. Fourth, the moveable marks can be accidentally moved. Fifth, the overall appearance of the faucet becomes less attractive.
In U.S. Pat. No. 6,283,447, Fleet proposes a fixed mark on valve handle, and a moveable mark on a small part connected to a rotating ring. There are several drawbacks in Fleet's approach: First, user needs to take two simultaneous actions (i.e., to pull and rotate) in order to move the moveable mark. Second, the moveable mark on a small moving part is difficult to maneuver. Third, the moveable mark uses a small resilient hinge to stabilize its position. As a result, it can fail due to fatigue of the resilient hinge, or due to large pulling force exercised by user. Fourth, the moveable mark is difficult to be cleaned. Mildew can build up in the hidden area behind the moveable mark. Fifth, it is impossible to clean the hidden area behind the moveable mark without moving the moveable mark. As a result, the moveable mark needs to be pre-set each time after cleaning.
Therefore, there is still a need for a new approach to solve the above problems and overcome all the drawbacks of prior approaches.
The new approach of present invention is to add a second rotating element to a conventional mixing valve. The conventional mixing valve typically has only a single rotating element (i.e., valve handle) connected to a valve stem. This can be done by constructing a new rotating element, or converting an existing stationary element to a rotating element. In either case, the second rotating element becomes an integral structure of the mixing valve assembly. The second rotating element of present invention rotates about the axis of the valve stem. A fixed mark, referred to as the second mark hereinafter, is provided on the outer surface of the second rotating element. Another fixed mark, referred to as the first mark hereinafter, can be provided either on the outer surface of a stationary element, or on the outer surface of valve handle (i.e., first rotating element).
In the case that the first mark is provided on the valve handle, the valve handle and the second rotating elements must rotate independently so that there is a relative movement between first and second marks. The valve handle can be pre-set to the desired temperature position as follows: First, rotate the valve handle to the desired temperature position by trial-and-error. Second, rotate the second rotating element to a stop position where second mark meets first mark. After the valve handle is pre-set, user can rotate the valve handle directly to the desired temperature position by aligning first mark to second mark.
In the case that first mark is provided on a stationary element, valve handle and the second rotating elements must rotate concurrently so that there is no relative movement between valve handle and the second rotating element, but there is a relative movement between first and second marks. The valve handle can be pre-set to the desired temperature position as follows: First, rotate valve handle to the desired temperature position by trial-and-error. Second, rotate the second rotating element to a stop position where second mark meets first mark. After the valve handle being pre-set, user can rotate the handle directly to the desired temperature position by aligning second mark to first mark.
One distinctive aspect of present invention is to provide a second rotating element, which is an integral part of the valve assembly. As a result, the overall appearance of the valve assembly remains unchanged. In other words, there is no adverse impact to the overall appearance of the valve assembly due to the addition of the second rotating element.
Another distinctive aspect of present invention is to eliminate the need for a small moving part serving as a moveable mark. As a result, the present invention overcomes all the drawbacks caused by using the small moving part in prior art.
Another distinctive aspect of present invention is to eliminate the use of multiple moveable marks. The reasons are as follows: (1). Multiple moveable marks can be confusing. (2). Any second user, other than the person who pre-sets the valve handle, can be benefited by the pre-set marks. This is because the second user can avoid the possibility of being scaled, and adjust the valve handle to the desired temperature position in a smaller range. (3). In the case of commercial use such as in hotel, the present invention allows house maid to pre-set the handle position to a comfortable temperature.
Another distinctive aspect of present invention is that the second rotating element is provided with limit stops for restricting maximum forward and rearward axial movements without using conventional set screws. Such limit stops prevent the possibility of the second rotating element being accidentally detached from the valve assembly. This also enhances the overall appearance of the valve assembly.